The object of the invention is a sleeve part of a pipe joint as defined in the preamble of claim 1, which sleeve part comprises a chamber space, into which the opposing butt ends of the pipe parts to be connected together are placed essentially against each other such that the sleeve part extends a distance from the point of connection of the pipe parts to be connected together on top of both pipe parts, which sleeve part comprises heating means, such as resistance wires, as a consequence of the heating of which resistance wires a joint forms between the sleeve part and the pipe parts.
The object of the invention is also a pipe joint as defined in the preamble of claim 6.
Bushing joints are generally used for connecting together pipes, more particularly plastic pipes, end-on-end. The point of connection is placed into the bushing, i.e. into the sleeve part, such that the ends of the pipe parts to be connected together are inside the bushing and the bushing is thus around the point of connection extending some distance in the longitudinal direction of the pipes from the point of connection in both directions. The bushing part is provided with thermal resistors or corresponding, in which case when forming the joint electric current is conducted to the resistors, in which case the resistors heat up and a joint forms between the sleeve part and the pipe parts. The type of joint described has the problem, particularly when applied in the joints of the transfer pipings of pneumatic waste-transporting systems, that a gap or sill that is detrimental to the transportation of material can remain between the pipe parts to be connected. In prior-art solutions the bushing can contain a countersurface against which the pipe parts to be connected together should be placed, but in practical installation conditions installation errors that result in an unsatisfactory joint can remain in the placement of the pipes into the bushing. Thermoplastic pipe joints of the type described above are described e.g. in the publications U.S. Pat. Nos. 2,739,829, 4,530,521 and 4,906,313. Known from publication JP2003343788 is a solution wherein a transparent part is formed in the bushing, from which transparent part the ends of the pipes can be seen.
The purpose of this invention is to achieve a completely new type of solution for a pipe joint, by means of which the problems of prior-art solutions can be avoided. One important aim is to achieve a pipe joint solution applicable to the conveying pipings of pneumatic waste transporting systems. Yet another aim is to achieve an easily installable solution for a pipe joint, by means of which the point of connection can be inspected, even before welding, and to which measuring devices can easily and reliably be permanently or temporarily connected.